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Author: Richeal Ni Riordain, Elective Medical Student at Barts and The London School; Chief Editor: A/Prof Amanda Oakley, Hamilton, New Zealand, May 2014.
Torus is a bony growth or protrusion that can occur on either the upper jaw (maxillary torus) or the lower jaw (mandibular torus). The word torus (pl. tori) is Latin, meaning swelling or protuberance. The growth is also called a bony exostosis.
Torus is more common in the upper jaw, where it usually occurs in the middle of the palate (the roof of the mouth). In the lower jaw, tori develop near the premolar teeth, and commonly occur on both the right and left side of the lower jaw.
Tori are common, with as high as 65% prevalence reported worldwide1. Tori can develop in men and women with maxillary tori more common in females2. The average age for a torus to develop is between 30-40 years old3 although upper jaw tori have been discovered as early as the first decade in life4.
A torus can present as a single bony protrusion or a cluster of multiple bony protrusions. An upper jaw, or maxillary, torus presents as a bony lump in the middle of the palate. Lower jaw, or mandibular, tori present as bony lumps on the right and left of the jaw, along the surface that abuts the tongue, near the premolar teeth. Although mandibular tori are more common on both the right and left together, a torus may occur on either side alone.
Tori have very slow growth, which can stop spontaneously. They present in a variety of shapes, are hard to the touch and have a smooth surface. Sometimes, as the covering (mucosa) of the bony lumps is stretched, they have a less pink appearance compared to the rest of the mouth.
The exact cause of tori developing in the jaws is unclear. A number of factors may be involved, including genetics, biting and chewing habits and local injury or trauma5, 6, 7.
Tori are usually a chance finding at a routine dental visit. They are generally painless. As tori protrude from the surface they can sometimes be discovered when the overlying mucosa (skin of the mouth) has been injured by rough or sharp food resulting in an ulcer forming. X-rays and biopsies are of no benefit, and diagnosis is based on examination of the mouth.
No treatment is required in most cases. Rarely, a torus can impede a denture and in these cases surgical removal can be considered.
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